This invention relates to cue addressing apparatus and, more particularly, to such apparatus which is readily adapted for use in signal editing apparatus, whereby a selected position of either a playback or record medium, such as video tape, can be accessed.
In the field of signal recording, it often is desirable to modify or edit a recording by selectively inserting thereinto various bits and pieces which are derived from other recordings. Video signal editing has become a highly specialized and advantageous art, whereby video signals which are recorded on a particular record medium, such as a magnetic tape, a magnetic disk, or the like, are edited by selectively assembling or inserting other video signals onto that record medium. For the purpose of the present discussion, the record medium on which the video signals are recorded is described as magnetic tape which, presently, is the most common form of record medium that now is used for recording video programs. Typically, in the field of broadcast and commercial video tape recording, video signals which are recorded on one tape are reproduced by a video tape recorder (VTR) for an "insert" or "assemble" recording on another tape by another VTR. As is known to those of ordinary skill in the art of video editing, an "insert" edit operation describes the insertion of video signals into a predetermined location on a video tape, the "inserted" signals being preceded and followed by pre-existing video signals. In an "assemble" mode of operation, video signals are recorded in following reaction (i.e. assembled) to pre-existing information.
As is recognized, to carry out the insert and assemble edit modes of operation, it is necessary for an operator to select appropriate portions, or blocks, of video signals which are to be reproduced from one tape (referred to generally as the source or playback tape) and which are to be recorded at other locations on the recording (or destination) tape. That is, the operator must be aware of the particular addresses on the source tape at which desired video signals are recorded as well as addresses on the destination tape at which new video signals are to be placed. These "addresses" on the respective video tapes generally are recorded as time code addresses, each of which separately identifies a respective frame of the recorded video signal. An example of one type of time code address which is used with, for example, the recording of NTSC signals is the so-called SMPTE (Society of Motion Picture and Television Engineers) time code which represents frame addresses in terms of hours, minutes, seconds and frames, up to a maximum value of 23 hours, 59 minutes, 59 seconds and 29 frames. Although other acceptable time code addresses are known, for convenience, and in the interest of simplification, the present discussion refers only to this SMPTE time code.
It is conventional to record the time code longitudinally, that is, in serial tracks along a length of the video tape. Time code generators and readers are known for the recording and reading of such time codes as the video tape is transported. These time codes, as read from the video tape, are used to designate so-called "edit-in" and "edit-out" locations of the respective playback and recording tapes.
To carry out an edit operation, the time code addresses which identify the particular frames on the playback tape which define the video information that is to be re-recorded on the recording tape are marked, or stored, as the edit-in and edit-out points. For an insert edit mode, the desired edit-in and edit-out points on the recording tape likewise are marked, or stored. Once an operator confirms that the material, or video signals, lying between the edit-in and edit-out points on the playback tape is correct and should be re-recorded, or transferred, between the edit-in and edit-out points on the recording tape, the actual transfer of video signals may occur. Such confirmation of this edit operation is known as a "preview", and the previewed operation may be monitored on a suitable video display monitor device. If changes are to be effected to the respective edit-in and edit-out points, for example, if the operator finds other material which he wishes to transfer from the playback tape to the recording tape, or material which should be deleted from the recording tape, the time code addresses which define the respective edit points may be suitably changed.
In establishing the various parameters for carrying out an edit operation, the operator often wishes to ascertain the information which is present at various locations on either or both the playback tape and the recording tape. This is first attained by a "cue" operation wherein a selected tape is advanced (or rewound) to a particular location, identified as the cue address. Once this particular location is reached, the operator may verify the information recorded thereat, and determine whether such information should be used in the edit operation.
Typically, in performing a cue operation, the operator may wish to advance, or "cue", the playback or recording tape to its respective edit-in point, its edit-out point, or some arbitrary (or preselected) point therebetween. It also may be desirable to cue the tape to any other randomly desired point. Cue control apparatus is known whereby either tape may be rewound to a preset location prior to its selected edit-in point. Other control apparatus is known whereby either tape may be scanned (or "searched") until a pre-set address thereon is reached, this pre-set address being determined by operator-control of a numerical keyboard. However, such cue control apparatus is not readily capable of simple operation whereby an operator can command cuing of either tape to any one of a number of preselected addresses. For example, such apparatus does not easily allow the operator to cue the tape to displayed addresses merely by operating simple push-button switches associated with such displayed addresses. Rather, the desired address must be "keyed" in via a suitable keyboard, with the resultant possibility of erroneous operation and the consequential cuing to an improper location.
Furthermore, in preparing for an edit operation, the operator may wish to transfer a particular segment of predetermined length from the playback tape to the recording tape, commencing at an appropriate edit-in point on the recording tape. However, he may be uncertain of the material already present on the recording tape, and which will follow the inserted segment as a result of the edit operation, is satisfactory. Under these conditions, the operator would wish to examine that material. Desirably, this can be achieved by cuing the recording tape to an address, or location, corresponding to the edit-out point on the playback tape. In known cue control apparatus, it would be necessary for the operator to calculate the duration of the inserted segment, to add this duration to the edit-in point on the recording tape so as to derive a suitable address, and then to advance the recording tape to that address. Not only are the necessary data calculations in arriving at the proper cue address time-consuming and laborious, but they are subject to errors which would result in the wrong cue operation. Furthermore, to carry out this cue operation on such cue control apparatus requires the particular expertise of a highly skilled technician. It is desirable to provide apparatus which can perform this cue operation under the control of an operator who need not necessarily possess such expertise and, moreover, which is provided with simple push-button controls to facilitate operation. Also, such apparatus should provide appropriate indications to the operator so that he will be apprised of the parameters which he is selecting for such a cuing operation.
It is advantageous to provide cue control apparatus having the aforenoted capabilities for use with signal recording and/or playback devices in general. That is, although such cue control apparatus is particularly useful in signal editor devices, and especially video editors, it is desirable to furnish cue control apparatus having wide flexibility and adaptability in, for example, data recorders, video recorders, audio recorders, and the like.